1. Field of the Invention
The present invention relates to a highly stretched polarizing film having an excellent light transmittance, a polarization degree and surface smoothness. The present invention relates to also a polarizing plate and an optical element using the same.
2. Description of the Related Art
Polarizing films composed of stretched polyvinyl alcohol films are known in the art. As liquid crystal displays have become more common, further improvement in a light transmittance and a polarization degree has been sought. One suggestion for improving these features is to provide conventional polyvinyl alcohol films stretched at a higher ratio.
However, such a polarizing film has a problem that the high stretch ratio induces streaks like a groove on a record and that the streaks are recognized easily to inhibit the visibility in a reflection mode. The streaks look like stripes in the stretching axis direction and appear in general as irregularity having a centerline average roughness of at least 0.06 μm with average spacing in a range from 0.6 mm to 0.8 mm.